We thank E. Bombardelli for 10-deacetylbaccatin III, K. B. Sharpless for a series of diols, and I. Ojima for the β-lactam 6. This work was supported by The Scripps Research Institute, National Institutes of Health (USA), Office of Naval Research (USA) (R. K. G.), Natural Sciences and Engineering Research Council (Canada) (J. R.), the Agricultural University of Athens (E. A. C.), and Rhone-Poulenc Rorer (P. G. N.).

ARTICLE TOOLS

Nucleophilic ring opening of cyclic carbonates 1 leads regioselectively to the less substituted ester 2. Moreover, for molecules with several carbonyl groups the reaction is chemoselective: In a taxol precursor the carbonate group and not one of the three additional carbonyl groups was attacked; the resulting esters were converted into taxol analogues that displayed differing cytotoxicities.